Power manager

ABSTRACT

An improved power manager includes a power bus ( 410 ) and multiple device ports ( 1 - 5 ), with at least one device port configured as a universal port ( 3  and  4 ) to be selectively connected to the power bus over an input power channel that includes an input power converter ( 510 ) or over a output or universal power channel ( 412, 416 ) that includes an output power converter ( 440, 442 ). The universal power channel ( 412 ) allows the input port ( 4 ) to be selected as an output power channel instead of an input power channel (i.e. operated as a universal port) for outputting power to device port ( 4 ) over power converter ( 440 ). The improved power manager ( 500 ) includes operating modes for altering an operating voltage of the power bus ( 505 ), to minimize overall power conversion losses due to DC to DC power conversions used to connect non-bus voltage compatible power devices to the power bus.

1 CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/807,028, filed Apr. 1, 2013, which is incorporated herein byreference.

2 BACKGROUND OF THE INVENTION

2.1 Field of the Invention

The exemplary, illustrative, technology herein relates to power managersystems suitable for operably connecting one or more power sources andone or more power loads to a power bus and distributing power from thepower sources to the power loads over the power bus. The improved powermanager includes at least one universal port that can be operated as aninput port to receive input power from a power source and that can alsobe operated as an output port to deliver output power to a power load.Additionally the improved power manager includes system and operatingmethod improvements provided to reduce power loss stemming from DC to DCpower conversions.

2.2 The Related Art

Referring to FIGS. 1 and 2, a conventional power manager (100, 200)includes a Direct Current (DC) power bus (105) and six power ports (110,130) operably connectable with the power bus. Up to six external powerdevices (115, 120) can be connected, one to each of the six device ports(110), and all six external power devices can be operably connected tothe power bus (105) simultaneously. In one particularly relevantembodiment disclosed in U.S. Pat. No. 8,633,619 to Robinson et al.entitled Power managers and method for operating power managers, issuedon Jan. 21, 2014; a power manager is disclosed that includes six deviceports. The power manager system disclosed by Robinson et al. is shownschematically in FIGS. 1 and 2. In FIG. 1, a power manager (100)includes six device ports with two input device ports (130) and fouroutput device ports (110). When all the device ports are connected toexternal power devices each device port (110, 130) is connected to aninput power or energy source (115) or to a power load (120).

Each device port is operably connectable to a power bus (105) byoperating one or more controllable switches. In an initial state eachcontrollable switch is open (shorted) to disconnect the device port fromthe power bus. An electronic controller (125, 205) operates thecontrollable switches according to an energy management schema programor firmware running on the electronic controller. The electroniccontroller also communicates with each external device (115, 210) orwith a smart cable associated with the external device to determine itsoperating voltage range and other power characteristics. The electroniccontroller continuously monitors external devices connected to thedevice ports and continuously evaluates if each connected external powerdevice is a power source or a power load and further determines whetherthe external power device can be connected to the power bus (105) ornot. In the event that the electronic controller determines that theconnected external device is not compatible with connecting to the powerbus the device is not connected. In the event that the electroniccontroller determines that an external device already connected to thepower bus is no longer compatible with connecting to the power bus thedevice is disconnected by actuating a controllable switch.

The power manager (100, 200) is configured as a Direct Current (DC)device suitable for use with DC power sources and DC power loads. Theconventional power bus (105) operates at a substantially fixed DCvoltage. While the fixed bus DC voltage may fluctuate as power loads andpower sources are connected to or disconnected from the power bus (105)the power bus voltage is substantially maintained within a small voltagerange, e.g. 10-14 volts or the like, referred to herein as a“bus-compatible voltage.”

When an external power device (115, 120) is determined to be operable ata bus-compatible voltage the external power device (115, 120) ispreferably directly connected to the power bus without any powerconversion. Thus power sources and power loads that can operate at thebus-compatible voltage can be directly connected to the power bus (105)over any one of the device ports (110) or (130) without the need for avoltage conversion. This is demonstrated in FIG. 2 which shows aschematic representation of a pair of input device ports (130 a) and(130 b) each connectable to the power bus (105) over two differentconnection paths and a pair of output device port (110 a) and (110 b)each connectable to the power bus (105) over two different connectionpaths. As shown, each input device port (130 a, 130 b) includes a firstpower channel (1080) that extends between the device port (130 a) andthe power bus (105) and another first power channel (1085) that extendsbetween the device port (130 b) and the power bus (105). As also showneach first power channel (1080, 1085) includes a first controllableswitch (1040) disposed between port (130 a) and the power bus and firstcontrollable switch (1030) disposed between port (130 b) and the powerbus. Similarly each output port (110 a, 110 b) also includes a firstpower channel (1090, 1095) and a first controllable switch (1055)disposed between the output port (110 a) and the power bus (105). Thusall six device ports include a first power channel for directlyconnecting an external device connected to the device port to the powerbus when the first controllable switch is closed.

In operation the first controllable switch is opened preventing theexternal device from connecting with the power bus (105). The electroniccontroller (125) communicates with each external power source (115 a,115 b) and with each external power load (120 a, 120 b) to determineoperating voltages of each externally connected power device. If any ofthe connected external devices are operable at the bus compatiblevoltage the electronic controller (125) can actuate (close) the relevantfirst controllable switching elements (1030, 1040, 1055, 1060) todirectly connect all of the external devices that can operate at the busvoltage to the power bus if other conditions of the energy managementschema justify the connection. Moreover in the case where a power sourceor a power load is operable at the bus compatible voltage power sources(115 a, 115 b) and the power loads (110 a, 110 b) are interchangeablebetween the input device ports (130 a, 130 b) and the output ports (110a, 110 b). More generally every device port (110) can be used as ininput device port or an output device port when the connected externaldevice is operable at the bus-compatible voltage.

Alternately when a connected external device is not operable at thebus-compatible voltage it can be connected to the power bus over a DC toDC power converter when the power converter is configurable to perform asuitable voltage conversion. This is demonstrated in FIG. 2 wherein thetwo input device ports (130 a, 130 b) share a single input powerconverter (1065) and the two output device ports (110 a, 110 b) share asingle output power converter (1070). Each power converter (1065) and(1070) is unidirectional such that the power converter (1065) can onlymake a power conversion on an input power signal received from a powersource (115 a, 115 b) and the power converter (1070) can only make apower conversion on an output power signal received from the power bus(105).

The input ports (115 a, 115 b) share the input power converter (1065)over a second power channel (1075). The channel (1075) is accessed bythe device port (130 a) by opening the switches (1040) and (1035) whileclosing the switch (1025) such that a power signal received through theinput device port (130 a) flows over the second power channel (1075) andthrough the power converter (1065) to the power bus (105). The channel(1075) can also be access by the device port (130 b) by opening theswitches (1030) and (1025) and closing the switch (1035) such that apower signal received through the input device port (130 b) flows overthe second power channel (1075) and through the power converter (1065)to the power bus (105). Thus one of the two input power sources (115 a)and (115 b) can be connected to the power bus over the input powerconverter via the second power channel (1075), both of the two inputpower sources (115 a) and (115 b) can be connected to the power bus overthe two first power channels (1080) and (1085) or one of the two inputpower sources (115 a) and (115 b) can be connected to the power bus overthe input power converter via the second power channel (1075) while theother of the two input power sources (115 a) and (115 b) is connected tothe power bus over the relative first channel (1080) or (1085).

Similarly the output ports (110 a, 110 b) share the output powerconverter (1070) over a second power channel (1097). The channel (1097)is accessed by the device port (110 a) by opening the switches (1045)and (1055) while closing the switch (1050) such that a power signalflowing from the power bus (105) to the output port (110 a) flowsthrough the output power converter (1070) and over the second powerchannel (1095) to the power load (120 a). The channel (1075) can also beaccessed by the device port (110 b) by opening the switches (1050) and(1060) and closing the switch (1045) such that a power signal flowingfrom the power bus (105) to the output port (110 b) flows through theoutput power converter (1070) and over the second power channel (1095)to the power load (120 b).

Thus one of the two power loads (120 a) and (120 b) can be connected tothe power bus over the output power converter via the second powerchannel (1097), both of the two power loads (120 a) and (120 b) can beconnected to the power bus over the two first power channels (1090) and(1095) or one of the two power loads (120 a) and (120 b) can beconnected to the power bus over the output power converter via thesecond power channel (1095) while the other of the two power loads (120a) and (120 b) is connected to the power bus over the relative firstchannel (1090) or (1095). While not shown in FIG. 2 the remaining pairof output device ports (totaling six ports) is configured like theoutput device ports (110 a) and (110 b). Thus all six device ports ofthe device (100) include a first power channel for directly connectingan external device connected to the device port to the power bus whenthe first controllable switch disposed along the first power channel isclosed. Meanwhile at the two input device ports (130 a) and (130 b)share an input power converter and each pair of output device portsshares an output power converter.

2.2.1 Empty Input Device Ports not Utilized

Accordingly one problem with the device disclosed by Robinson et al. isthat for a given pair of device ports only one of the device ports hasaccess to a power converter. In the case of the input device ports (130a, 130 b) the input power converter (1065) can operate with one powerconversion setting, e.g. to step up or step down the input voltage tomatch the bus voltage. Thus if two input sources are available and eachhas a different non-bus compatible operating voltage, only one of thetwo input sources is usable and one of the input device ports isavailable. While the unused input port can be used as an output port fora power load that is bus voltage compatible there is no opportunity touse the empty input port for a non-bus compatible voltage device. Theproblem also extends to the output side. As a result one of the inputports is not usable. In the case of the output device ports (110 a, 110b) and other pairs on the power manager, the output power converters(1065) can operate with one power conversion setting, e.g. to step up orstep down the bus voltage to match the connected non-bus voltagecompatible power load. Thus if two power loads are in need of power andeach has a different non-bus compatible operating voltage, only one ofthe two power loads can be powered and one of the two output deviceports associated with the output power converter is available. While theunused output port can be used as an output port for a power load thatis bus voltage compatible there is no opportunity to use the emptyoutput port for a non-bus compatible voltage device.

Thus one problem that arises with conventional power managers that donot include a power converter for each device ports is that not all theavailable device ports can be utilized to power loads that require apower conversion. In one example, the bus is powered by a single powersource connected to one of the input device ports (130 a, 130 b) andthere are more than four power loads that need power. In this examplefour power loads may be able to be powered at the four output ports(110) but one of the input ports (130) is empty. While the empty inputport can be utilized to power a load with a bus compatible operatingvoltage there is a need to utilize the empty input port to power a loadthat needs a power conversion. More generally there is a need to utilizeempty input and output device ports to power loads that require a powerconversion.

2.2.2 Power Loss Resulting from Each Power Conversion

A further problem in the art relates to suffering power lossesassociated with each power conversion. As is well known, each powerconversion (e.g. a buck/boost converter) has an associated power loss inproportion to the input and output voltage and the input and outputcurrent amplitude. The power loss for such a conversion for a definedset of input and output currents can be approximated by:PLoss=Ls(|Vin −Vout|)  Equation 1where the power loss PLoss is the power lost due to the voltageconversion for given input and output current amplitudes, Ls is a lossfactor associated with the particular power converter or type of powerconverter, Vin is the input voltage, and Vout is the output voltage.Thus the power loss is directly proportional to the step up or step downvoltage.

2.2.3 Fixed Bus Voltage can Lead to Power Loss

When a power manager (e.g. 200) is operated with a fixed bus voltage,unnecessarily large step up and step down voltage conversions aresometimes performed, leading to unnecessary power loss. Moreover, asdescribed above, operating a power manager with a fixed bus voltage canlead to empty device ports that are not usable to power loads. Since allthe device ports of the device shown in FIG. 2 include a power channelto directly connect a power device to the power bus without a powerconversion, allowing the bus voltage to match the voltage of at leastsome of the power devices connected to the power bus can help to avoidpower conversions. Alternately reducing the step up or step down voltageat each converter can also reduce power conversion losses.

In a conventional operating mode, a fixed bus voltage ranges from 12-16volts, but the user has a 30 volt power supply and a plurality of 30volt power loads that need to be connected to the power manager. In thiscase, each 30 volt device requires a power conversion to connect to thepower bus. When each device is power converted, power losses occur ateach device port. Given that in many cases, power managers are used inremote locations to simultaneously power a plurality of power loadsusing limited input power resources, a power loss at every device portis not desirable. Thus, there is a need in the art for a power managerthat can adapt its bus voltage according to the configuration of powerdevices connected to it to reduce power loss and maximize device portutilization.

3 SUMMARY OF THE INVENTION

In view of the problems associated with conventional methods andapparatus set forth above, it is an object of the present invention toimprove device port utilization by making more device ports available topower additional non-bus voltage compatible power loads.

It is a further object of the invention to reduce power loss associatedwith power conversions by performing fewer power conversions.

It is a further object of the invention to reduce power loss when powerconversions are performed by reducing the quantity |Vin−Vout| listed inEquation 1.

It is a still further object of the present invention to provide a powermanager that operates at a plurality of different bus voltage operatingpoints.

It is a still further object of the present invention to determine a busvoltage operating point that reduces power loss according to theoperating voltages of connected power devices.

4 BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention will best be understood from adetailed description of the invention and example embodiments thereofselected for the purposes of illustration and shown in the accompanyingdrawings in which:

FIG. 1 illustrates a schematic diagram representing a conventional powermanager having six device ports connected to a power bus with 2 deviceports configured as input ports and four device ports configured asoutput ports.

FIG. 2 illustrates a schematic diagram representing a portion of aconventional power manager with two input ports sharing an input powerconverter and two output ports sharing and output power converter.

FIG. 3 illustrates a schematic diagram representing a first non-limitingexemplary embodiment of a power manager having an improved power channellayout according to the present invention.

FIG. 4 illustrates a schematic diagram representing a secondnon-limiting exemplary embodiment of a power manager having an improvedpower channel layout and control system according to the presentinvention.

FIG. 5 illustrates a schematic diagram representing a third non-limitingexemplary embodiment of an improved power manager having a variablevoltage power bus according to one aspect of the present invention.

5 DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

5.1 Overview

5.1.1 Expanded Access to Power Converted Output

In exemplary, non-limiting, embodiments of the invention an improvedpower manager operating with a fixed bus voltage includes additionalpower channels and related control elements for routing power from anoutput power converter to a plurality of device ports, including todevice ports associated with an input power converter. The additionalpower channels allow a user of the power manager to connect power loadsto input device ports even when the power load connected to the inputdevice port operates with a non-bus compatible voltage. In one exampleembodiment shown in FIG. 3, a single input device (115 b) is used topower three power loads (110 a, 110 b, 110 c) over a single outputconverter (3070), as illustrated by bold arrows, indicating flow ofpower from power source (115 b) to power loads (110 a, 110 b, 110 c).This in an improvement over conventional power manager (200) which islimited to powering only two power loads (110 a, 110 b) over a singlepower converter (1070).

In a further example shown in FIG. 4, a single input source connected topower manager (400) at device port (3) is used to power three powerloads, power loads at ports (1, 2, and 6), over a single output powerconverter (440) by providing an additional power channel (414) andassociated controllable switch (484). This is an improvement overconventional power managers which are limited to powering only two powerloads over a single power converter. In further embodiments, additionalpower channels are provided to power more than three device portsthrough a single output power converter (440). Meanwhile each of thedevice ports of the improved systems (300) and (400) each includes afirst power channel and first controllable switch provided to connectany bus compatible voltage power device connected to any device port tothe power bus without passing over a power converter.

5.1.2 Bus Voltage Varied to Reduce Power Conversion Losses

In exemplary, non-limiting, embodiment of the invention an improvedpower manager (500), shown in FIG. 5, manages the device bus voltageaccording to the collective operating voltages of external power devicesconnected to the power bus. The power manager further includes anelectronic controller and a communications interface module wherein thecommunications interface module connects the electronic controller tothe each device port, to sensors measuring power conditions on the powerbus and to other components of the power manager. The controllerreceives information regarding the external devices connected to thepower manager and controls components of the power manager to set thebus voltage, to set power conversion parameters of the power converters,and to connect and disconnect device ports to and from the power busaccording to an energy management schema. The controller is furtherconfigured to collect operating voltage parameters of each externalpower device connected to a device port and to calculate a bus voltagethat minimizes power losses due to power conversions required by powerconverters to connect power devices to the power bus. The need for apower manager that reduces power losses due to power conversions is metby providing a power manager with a variable bus voltage wherein the busvoltage is set to a value that minimizes power losses due to conversionof input and output power to accommodate attached power sources andpower loads.

These and other aspects and advantages will become apparent when theDescription below is read in conjunction with the accompanying Drawings.

5.2 Item Number List (if Applicable)

The following item numbers are used throughout, unless specificallyindicated otherwise.

# DESCRIPTION # DESCRIPTION 100 Power Manager 400 Power Manager 105Power Bus 405 Electronic Controller 120 Device Port (Output Port) 403Communication Interface 115 External Device Power Source 3 Device Port(Input Port/Universal Port) 110 External Device Power Load 4 Device Port(Input Port/Universal Port) 125 Electronic Controller 5 Device Port(Output Port) 130 Device Port (Input Port) 6 Device Port (Output Port) 1Device Port (Output Port) 200 Power Manager 2 Device Port (Output Port)205 Electronic Controller 410 Power Bus 210 Communication Interface 402Direct Power Channel (Port 3) 1065 Input Power Converter 404 DirectPower Channel (Port 4) 1070 Output Power Converter 406 Direct PowerChannel (Port 2) 1025 Switching Element 408 Direct Power Channel(Port 1) 1030 Switching Element 535 Direct Power Channel (Port 6) 1035Switching Element 525 Direct Power Channel (Port 5) 1040 SwitchingElement 470 FET 1045 Switching Element 475 FET 1050 Switching Element450 FET 1055 Switching Element 455 FET 1060 Switching Element 460 FET1080 Non-Converted Power Channel 465 FET 1085 Non-Converted PowerChannel 510 Input Power Converter 1090 Non-Converted Power Channel 532Input Converter Power Channel 1095 Non-Converted Power Channel 503 FET1075 First Conductive Channel 505 FET 1097 Second Conductive Channel 440Output Power Converter 435 Output Converter Power Channel 300 ImprovedPower Manager 485 FET 305 Power Bus 480 FET 330 Universal Port 442Output Power Converter 3080 Direct Power Channel 530 Output ConverterPower Channel 3085 Direct Power Channel 495 FET 3090 Direct PowerChannel 490 FET 3095 Direct Power Channel 412 Additional Power Channel(Port 4) 3065 Input Power Converter 482 FET 3075 Input Converter PowerChannel 416 Additional Power Channel (Port 3) 3070 Output PowerConverter 486 FET 3097 Output Converter Power Channel 310 AdditionalPower Channel 500 Power Manager 315 Controllable Switch 505 Power Bus320 Controllable Switch 550 Electronic Controller 325 ControllableSwitch 555 Communication Interface 560 Bus Sensor Module 510 Input PowerConverter 515 Input Power Converter 520 Output Power Converter 525Output Power Converter 503 Input Device Port 504 Output Device Port 530Power Source 540 Power Load 5080 Non-Converter Power Channel 5085Non-Converter Power Channel 5090 Non-Converter Power Channel 5095Non-Converter Power Channel

5.3 Brief Description of the Invention

Referring to FIG. 3 an improved power manager (300) according to thepresent invention comprises a power bus (305) and a plurality of deviceports (330, 120) connectable to the power bus over a plurality ofindependent power channels. Each power channel includes one or morecontrol devices such as controllable switches (e.g., 1030, 1035, 1060,325) and controllable DC to DC power converters (3065, 3070) incommunication with an electronic controller (350). The electroniccontrol may comprise a microprocessor or the like, and a separate orintegrated data storage module (352) in communication with theelectronic controller (350). In addition a communications interface(354) such as SMbus or the like extends to each device port tocommunicate with external power devices connected with the device ports.In addition the communications interface (354) further includes elementsthat interconnect operable and passive electronic devices within thepower manager to the electronic controller (350) as required to operateswitches, to operate the power converters (3065) and (3070), and tocollect data from sensors and other electronic components.

Device ports (120 a, 120 b, 330 a, 330 b) are configured to interfacewith external power devices which may comprise power sources, powerloads, or rechargeable batteries (energy sources). Rechargeablebatteries may operate as an energy source when discharging to the powerbus or as a power load when recharging or drawing power from the powerbus. Throughout the specification when a power load is referenced it isunderstood that the term power load may encompass a rechargeable batteryor other rechargeable energy storage device that is recharging orotherwise drawing power from the power bus (305). Similarly, the termpower source is understood to encompass rechargeable batteries or otherrechargeable power devices that are discharging power to the power bus(305). It is further noted that in a preferred embodiment each deviceport comprises a physical connector or plug suitable for connecting toan external power device over a wire or cable that is terminated by aconnector or plug suitable for mating with the device port such thatexternal devices are easily connected to or disconnected from deviceports. It is further noted the preferred power manager (300) is aportable or more specifically man portable device and that the preferredpower manager is a DC to DC device exchanging power only with other DCdevices or devices that are converted to a suitable DC power signal.Additionally it is noted that the preferred device port includes a wirenetwork channel such that the power managers can at least receivedigital data from each external device connected to a device port over awire network interface using a network protocol such as SMbus, RS232,USB and the like.

In one example embodiment, the power bus operates with a substantiallyfixed bus voltage although the embodiment of FIG. 3 is not limited to afixed bus voltage device. The power manager includes control elementsand programs stored on the data storage module (352) and operable on theelectronic controller (350) for communicating with external powerdevices connected to device ports over the communication interface (354)to ascertain the device power characteristics, including a type andoperating voltage range of each connected external power device. If theexternal power device is bus-voltage compatible (i.e. has an operatingvoltage that overlaps with the power bus voltage) the external devicecan be directly connected to the power bus over a direct power channel(e.g. 3080, 3085, 3090, 3095) by closing appropriate control switches(e.g. 1030, 1040, 1055, 1060) and opening appropriate controllableswitches (e.g. 1025, 1035, 320, 325, 315 a and 315 b). Additionally, theelectronic controller (350) operates energy management schema programsthat select which external power devices to connect to the power bus(305) or to disconnect from the power bus (305) according to the overalloperating configuration and operating mode of the power manager (300).

If the external power device does not have a bus-voltage compatibleoperating voltage the external device can be connected to the power busover a power converter channel (e.g. 3075, 3097) that includes an inputpower converter (3065) for converting the input voltage of a powersource to a bus compatible voltage converting or an output powerconverter (3070) for converting bus voltage to a suitable output voltagefor powering a connected a power load. On the input side the input powerconverter (3065) can be configured to convert an input power signal byeither stepping the input voltage up or stepping the input voltage downas required to match the bus voltage. In the present example, switch(1035) is closed and switches (1025) and (1030) are opened in order todirect input power from the power source (115 b) to the power bus overthe input power converter channel (3070) which passes through the inputpower converter (3065). In another operating mode wherein the powersource (115 b) has a bus compatible voltage the port (330 b) isconnected directly to the power bus (305) without power conversion byopening the switches (1035) and (315 b) while closing the switch (1030).

The input and output power converters (3065) and (3070) are eachcontrolled by the electronic controller (350) and are each operable tostep the input voltage up or down as well as to modulate poweramplitude. Additional each device is unidirectional with the inputvoltage of the input power converter (3065) coming from the input ports(330 a, 330 b) and the input voltage of the output power converter(3070) coming from the power bus (305). Generally the power convertersoperate to modulate power amplitude passing over the power converterbetween a substantially zero and a maximum available power amplitude.Moreover the power converters substantially prevent power from passingfrom the output side to the input side.

Two power sources (115 a) and (115 b) each having the same non-buscompatible voltage can be, connected one to each of the device ports(330 a) and (330 b), and power converted simultaneously by directing theinput power from each of the device ports (330 a) and (330 b) over thepower converter channel (3075) to the power converter (3065) as long asboth external power sources require the same power conversion. In thisexample configuration, two power sources are connected to the power bus(305) over the power channel (3075) by opening and closing appropriatecontrol switches and by configuring the power converter (3065) for thedesired power conversion. In particular this is possible when switches(315 b), (315 a), (1030) and (1040) are open and switches (1035) and(1025) are closed. It is further noted that the power converter channel(3070) extends from the power bus (305) through the input powerconverter (3065) and branches onto tow paths to connect with each deviceport (330 a) and (330 b).

On the output side of the power bus the output power converter (3070)can be configured to power convert a power signal output from the powerbus (305) to power an external power load connected to either one orboth of the device ports (120 a or 120 b) over an output power converterchannel (3097). In particular the output power converter channel (3097)extends from the power bus to the output power converter (3070) and thenin two branches to each of the output device ports (120 b) and (120 a).In addition the power channel (3097) includes two controllable switches(325) and (320) which can be opened to disconnect a corresponding deviceport from the power bus or closed to connect a corresponding device portto the power bus over the output power converter. Accordingly, each ofthe external power loads (110 a) and (110 b) connected to the deviceport (120 a and 120 b) can be connected to the power bus over the outputpower converter (3070) when both loads (110 a and 110 b) have the samenon-bus compatible operating voltage. In either case the devices (110 aand 110 b) are connected to the power bus (305) over the output powerconverter channel (3097) by opening and closing appropriate controlswitches and by configuring the output power converter (3070) for thedesired power conversion.

As is the case on the input side, either or both of the output deviceports (120 a) and (120 b) can be connected directly to the power bus(305) without power conversion. In the case of output device port (120a) any power device that operates with a bus compatible voltage can beconnected to the power bus over the power channel (3095) by openingswitches (325) and (315 b) and closing switch (1060). In the case ofoutput device port (120 b) any power device that operates with a buscompatible voltage can be connected to the power bus over the powerchannel (3090) by opening switches (320) and (315 a) and closing switch(1055).

In a further aspect of the present invention two additional powerchannels (310 a and 310 b) are disposed one each from the output of thepower converter (3070) to two universal device ports (330 a and 330 b)respectively. Each power channel (310 a and 310 b) includes acontrollable switch (315 a, 315 b) in communication with the electroniccontroller (350) for opening and closing each switch to connect ordisconnect the appropriate power channel (310 a or 310 b) to deliverpower to a power load connected to one of the universal device ports(330 a or 330 b) or both. In particular the present invention andspecifically the power channels (310 a) and (310 b) allowed the inputports (330 a) and (330 b) to operate a universal port capable as beingused as an input port for input power sources that require powerconversion by an input power converter or as an output port for powerloads that require power conversion by an output power converter.

In one operating example a power source (115 b) is connected to thepower bus (305) over the input power converter (3065) through powerchannel (3075). Alternately the power source (115 b) can be directlyconnected to the power bus (305) over the power channel (3085) if thepower source has bus compatible operating voltage. On the output side,the power load (110 a) is connected to the power bus (305) over thepower converter (3070) by power channel (3097). Alternately oradditionally the power load (110 b) is also connected to the power bus(305) over the power converter (3070) by the power channel (3097). Inaddition the power channel (3097) extends to power channel (310 a) whenswitch (315 a) is closed such that a power load (110 c) connected to thedevice port (330 a) is also connected to the power bus over the outputpower converter (3070). In alternative operating modes, one or both ofthe power devices (110 a, 110 b) can be directly connected to the powerbus (305) without a power conversion over the power channels (3090 and3095) respectively and in that case one or both of the power devices(110 a and 110 b) may comprise a power load or a power source or arechargeable battery. In a further alternate operating mode the inputpower source (115 b) can be exchanged with a power load and connected tothe power bus over the output power converter (3070) using the powerchannel (310 b) when switch (315 b) is closed.

In another exemplary operating mode, either one or both of device port(330 a) and device port (330 b) can be connected to bus (305) over powerchannels (310 a) and/or (310 b), respectively, while one, both, orneither of device ports (120 a, 120 b) are simultaneously connected tothe power bus over output power converter (3070). In an exemplaryoperating mode one or both of device ports (120 a, 120 b), includes aconnected power source having a bus compatible voltage and therespective device port is connected to the bus (305) over anon-converted power channel (3095, 3090). In such an operatingconfiguration one or both of device ports (330 a, 330 b) may beconnected to bus (305) through output power converter (3070) overchannels (310 a, 310 b). Thus using a single power source having a buscompatible voltage connected to e.g. port (120 b) and directly connectedto the power bus (305) over the channel (3095) up to three power loadshaving the same non-bus compatible operating voltage can be powered fromthe output power converter (3070).

The power channel (3097) extends from the output end of a powerconverter (3070) to each of the device ports (120 a and 120 b) andincludes controllable switches (320 and 325) for connecting ordisconnecting the devices (110 a and 110 b) as required. The additionalpower channels (310 a and 310 b) extend the power channel (3097) to thedevice ports (330 a and 330 b) and include additional controllableswitches (315 a and 315 b) for connecting or disconnecting the deviceports (330 a) and (330 b) to the output converter (3070) as required.

Thus the improved power manager (300) includes at least one universalport, (e.g. 330 a or 330 b), capable of operating as an input port or anoutput port with selectable input or output power conversion.Specifically, when a power device connected to the universal port (330a) is determined to be a power source, the power source is eitherdirectly connected to the power bus over the power channel (3080) whenno power conversion is required, or the power source is connected to thepower bus over the input power converter (3065) using the power channel(3075), if the input power converter is available, i.e. not already inuse or not able to make the desired power conversion. Conversely, when apower device connected to the universal port (330 a) is determined to bea power load, the power load is either directly connected to the powerbus over the power channel (3080) when no power conversion is required,or the power load is connected to the power bus over the outputconverter (3070) if it is available, i.e. not already in use or not ableto make the desired power conversion. In particular the electroniccontroller (350) checks the status of the output power converter (3070)to determine if it can be configured to connect a power load connectedto the universal device port (330 a) to the power device. If the powerconverter is available (i.e. either not in use or not in use at anon-compatible power conversion setting), the power converter isconfigured with appropriate power conversion parameters to power he loadconnected to the universal port (330 a) and the switch (315 a) is closedto connect the power load (110 c) to the power bus over the powerconverter (3070). Meanwhile other switches that are opened or remainopened include (1040), (315 b) and possibly (320) and (325) depending onthe external devices are connected to device ports (120 a) and (120 b).

In operation, all the control switches in the power manager (300) areinitially opened to prevent current flow over any of the power channels.The electronic controller (350) then polls all of the device ports anddetermines if an external power device is connected and the power devicetype and power characteristics of each connected power device. Once thedevice types and characteristics are determined the energy managementschema selects a system configuration which includes generating a listof external devices to connect to the power bus, determining the powerconversion settings of each power converter, determining which powerchannel each device will be connected to the power bus over anddetermining which switches to open and close. Thereafter the electroniccontroller (350) periodically polls all of the device ports to updateconfiguration information and the energy management schema operates toadjust the connected power device configuration according to programparameters. Additionally the electronic controller (350) initiates thepolling process whenever a change in device configuration is detected,e.g. if an external device is connected or disconnected.

Typical example power and energy sources (115) include energy storagedevices such as batteries; a grid power source (e.g. a wall outletconverted to DC power); mechanically driven power generators (such asfossil fuel engines, wind, water, or other mechanically driven powergenerators); and/or current generators such as photovoltaic andelectrochemical devices. Example power loads (110) include any devicepowered by electricity, but usually include portable electronic devicesthat operate on a rechargeable DC battery or that operate on DC powerreceived from the power manager. In some instances, an input powersource may use an additional power conversion to become compatible withthe power manager. For example, if an AC power grid is available (120volts alternating at 60 Hz or 240 volts at 50 Hz), an additionalexternal power converter is used to invert the AC current and step theAC voltage down from the grid voltage to a DC voltage that is eitherdirectly compatible with the power bus voltage range or that can beconverted to the power bus voltage range using the DC to DC input powerconverter (3065). However, it is within the scope of the presentinvention to include a power converter within the power manager (300)that is configured to convert various AC power grid signals to a powersignal that is compatible with power bus voltage range.

5.3.1 Power Manager with Six Ports

Referring now to FIG. 4, a power manager (400) comprises six deviceports (1-6) operably connectable to a DC power bus (410). The power busis operating at 15 volts DC with some moderate voltage variabilityaround 15 volts (e.g. +/−3 volts) and is suitable for direct connectionwith external power devices having an operating voltage in the range of15+/−3 volts. Each of the six device ports can be directly connected tothe power bus (410) over a direct power channel (402, 404, 406, 408,535, and 525) respectively by closing controllable switches orfield-effect-transistor (FET), (470, 475, 450, 455, 460, and 465)disposed on each of the direct power channels between corresponding thedevice ports and the power bus. Each direct power channel extend fromthe device port to the power bus without power conversion and is used ifthe external device is operable at a bus compatible voltage e.g. 15+/−3volts, i.e. when the external device is bus-voltage compatible. In thecase where the external device is bus voltage compatible, the externaldevice is operable as a power source or as a power load irrespective ofwhether the external device is connected to an input port or an outputport. Power manager (400) includes an electronic controller (405) andassociated communication interface (403), shown by dashed lines,electrically interfaced to each device port (1-6), to each powerconverter (510, 440, 442), and to each FET, (e.g. 503, 505, 480, 485,482, 486, 490, 495). The communication interface (403) include a varietyof network communication paths suitable for digital data communications,e.g. between the electronic controller (405) and external devicesconnected to device ports as well as other conductive paths or the likesuitable for exchanging analog signals and or digital control signalse.g. with FET's voltage converters, sensors and other components of thepower manager.

The power manager (400) includes two input ports (3, 4) associated witha single unidirectional input power converter (510). The input powerconverter (510) has an input power conversion range (step up or stepdown) of 4 to 34 volts. Either of the input ports (3, 4) is usable toconnect an external power device to the power bus (410) over the powerconverter channel (532) that includes the power converter (510). Thus anon-bus voltage compatible power source connected to either one of theinput ports (3) and (4) can be connected to the power bus (410) over thepower converter (510) by closing either FET (503 or 505) when the powerconverter is operating at an appropriate step up or step down voltage.However the power converter (510) can only be used by one of the deviceports (3) and (4) unless each device port is connected to a power sourcethat requires the same power conversion setting to connect to the powerbus. For example if substantially identical 24 volt power sources areconnected to each of the device ports (3) and (4), each power source canbe connected to the power bus with a 9 volt step down conversion andboth devices can be simultaneously connected to the power bus over thepower converter (510) by closing both FETs (503, 505) At the same time,each of the FET's (486, 470, 482, 475) is opened to disconnect thechannels (416, 402, 404, 412) from the input device ports (3, 4 ).

The power manager (400) includes four output ports (1, 2) and (5, 6)each operably connectable to the power bus (410) and to external powerdevices suitable for connecting to the power bus. Output ports (1) and(2) are associated with a single unidirectional output power converter(440) disposed along an output power converter channel (435) whichextends from the power bus to the output power converter (440) andbranches to each of the ports (1, 2) over control switches (485) and(480). Output ports (5) and (6) are associated with a singleunidirectional output power converter (442) disposed along an outputpower converter channel (530) which extends from the power bus to theout power converter (442) and branches to each of the ports (5, 6) overcontrol switches (495) and (490). Each of the output power converters(440, 442) has an output power conversion range (step up or step down)of 10 to 24 volts. Either of the output ports (1, 2) is usable toconnect an external power load to the power bus (410) over the outputconverter power channel (435) that includes the output power converter(440). It is noted that the converter power channel (435) is shared bythe two ports (1, 2) and therefore can only be used for a single powerconversion by one of the device ports (1, 2) unless both of the deviceports can use the same power conversion. The output converter powerchannel (435) is accessed by port (1) by closing FET (485) and openingFET's (480), (455), (484) and (482).

Either of the output ports (5, 6) is usable to connect an external powerload to the power bus over the output power converter channel (530) thatincludes the output power converter (442). It is noted that the outputpower converter channel (530) is shared by the two ports (5, 6) andtherefore can only be used for a single power conversion by one of thedevice ports (5, 6) unless both device ports can use the same powerconversion. The output power conversion channel (530) is accessed byport (6) by closing FET (490) and opening FET's (495), (460), (484) and(486).

The power manager (400) further includes a power channel (412) thatextends from the output of power converter (440) by branching fromconverter power channel (435) to the input port (4) by branching to thedevice power channel (404). The power channel (412) allows a power loadconnected to input device port device port (4) to be connected to thepower bus (410) over the output power converter (440). In addition thepower manager (400) also includes a power channel (416) that extendsfrom the output of power converter (442) by branching from converterpower channel (530) to the input port (3) by branching to the devicepower channel (402). The power channel (416) allows a power loadconnected to input device port device port (3) to be connected to thepower bus (410) over the output power converter (442). In addition, thepower manager (400) also includes a power channel (414) that extendsfrom the output of power converter (440) by branching from converterpower channel (435) to both of the output ports (5) and (6) by branchingto the device power channel (530). The power channel (414) allows apower load connected to either of the output device ports (5) or (6) tobe connected to the power bus (410) over the output power converter(440). Alternately The power channel (416) can be used to connect apower load connected to either of the device ports (1) and (2) to thepower bus over the output power converter (442).

In operation, the electronic controller (405) polls each device port todetect connected external power devices and the power device type andpower characteristics of each connected power device. Once the devicetypes and characteristics are determined the energy management schemaselects a system configuration which includes generating a list ofexternal devices to connect to the power bus, determining the powerconversion settings of each power converter, determining which powerchannel each external power device will be connected to the power busover and determining which switches to open and close. Thereafter theelectronic controller (350) periodically polls all of the device portsto update configuration information and the energy management schemaoperates to adjust the connected power device configuration and powerdistribution according to program parameters. Additionally theelectronic controller (405) initiates the polling process whenever achange in device configuration is detected, e.g. if an external deviceis connected or disconnected.

5.3.2 Power Manager Operating with a Variable Power Bus Voltage:

Referring now to FIG. 5, a power manager (500) is depicted schematicallyand includes a power bus (505) interfaced with a plurality of inputpower converters (510, 515) and a plurality of output power converters(520, 525). Each input power converter is associated with an inputdevice port (503) for interfacing with an external power source (530)and each output power converter is associated with an output device port(504) for interfacing with an external power load (540). In alternateembodiments two or more ports may share a single power converter.

Each input device port (504) is connected to the power bus (505) over aninput converter power channel (570) which includes a controllable switch(565) in communication with an electronic controller (550). The inputconverter channel (570) extends from the input device port (503 a) tothe input power converter (515) over the controllable switch (565) andcontinues from the output of the power converter (515) to the power bus(505). Since the input converter is unidirectional power conversion isonly performed to change input voltage. Specifically the voltage of aninput power signal received from an external power source (530 a)connected to the input device port (503 a) can be stepped up or steppeddown to match the operating voltage of the power bus. The switch (565)is operable by the electronic controller (550) to connect the externalpower source (530 a) to the power bus over the input power converter(515) by closing the switch (565) and to disconnect the input deviceport (503 a) by opening the switch (565). Other converter input powerchannels have the same configuration.

Each output device port (504) is connected to the power bus (505) overan output converter power channel (578) which includes a controllableswitch (576) in communication with the electronic controller (550). Theoutput converter channel (578) extends from the output device port (504a) to the output power converter (520) over the controllable switch(576) and continues from the output of the power converter (520) to thepower bus (505). Since the output converter is unidirectional powerconversion is only performed to change output voltage. Specifically thevoltage of a power bus signal received from the power bus (505) can bestepped up or stepped down to match the operating voltage of ab externalpower load (540 a) connected to the device port (504 a). The switch(576) is operable by the electronic controller (550) to connect theexternal power source (540 a) to the power bus over the output powerconverter (520) by closing the switch (576) and to disconnect the outputdevice port (540 a) by opening the switch (576). Other converter outputpower channels have the same configuration.

Power manager (500) includes a non-converting power channel (5080, 5085,5090, and 5095) associated with each device port (503 a, 503 b, 504 a,504 b). The non-converting power channels are used to connect deviceports and any external power sources (530 a, 530 b) and external powerloads (540 a, 540 b) connected to device ports to the power bus. Eachconverted and non-converted power channel includes at least onecontrollable switching element (565, 566, 567, 568, 569, 572, 574, 578)that enables each power channel to be connected to or disconnected fromthe power bus. In additional embodiments, two or more input ports (503)or output ports (504) may share a single power converter as shown inFIGS. 3 and 4 above. In further embodiments, one or more input ports(503) may be configured as a universal port, i.e., selectivelyconnectable to the power bus over an input power converter or an outputpower converter, for example with a configuration similar to that shownfor ports (330) in FIG. 3.

An electronic controller (550) includes an associated data storagemodule and communication elements (555) suitable for exchanging commandand control signals and data signals with internal devises such as thecontrollable switches (565, 566, 567, 568, 569, 572, 574, 578), thepower converters (510, 515, 520, 525) the bus sensor module (560) andother internal modules as may be present. In addiction the communicationelements include a communication interface that extends between theelectronic controller (550) and each device port (503, 504). Moreovereach device port is configured as a connector or terminator thatincludes both power and communication channels suitable for connectingwith external power sources (530 a, 530 b), the power loads (540 a, 540b). Preferably the communication elements (555) includes at least onenetwork channel for data communication using a network protocol such asSMbus, USB, or the like for communicating with external devices.Otherwise the communication elements may comprise conductive paths,wires or the like, for exchanging analog signals between electroniccomponents of the power manager, e.g. switches, sensors and powerconverters and the electronic controller (550).

According to the present invention, the electronic controller (550)includes various modules operating thereon, including a data storagemodule, for operating an energy management schema suitable for changingoperating parameters of power manager elements e.g. to determine whichexternal device(s) to connect to the power bus over which power channelsand how power should be distributed as well as to alter an operatingvoltage of the power bus (505) in a manner that reduces power conversionloss. In one example embodiment, the electronic controller includesprograms operating thereon for operating the power bus (505) at one of aplurality of different operating voltages, as well as for reconfiguringpower converters and device port connections to the power bus inresponse in a change in power bus voltage.

In one example embodiment, the electronic controller (550) includes alook up table or the like stored in the memory module that lists aplurality of discreet bus voltage operating points, including a defaultbus voltage operating voltage. The preselected list of bus voltageoperating points is chosen to match the operating range of the variouspower converters (510, 515, 520, and 525). Thus, if all of the powerconverters are capable of making power conversions over a voltage rangeof 5 to 50 volts, the list of potential power bus voltages may includeoperating points within the 5 to 50 volt range that tend to matchstandard source/load voltages such as 6, 12, 24, 30, and 42 volts.Alternately, the power manager (500) is configurable to operate at anybus voltage that practically allows power devices to connect to thepower bus with or without a power conversion.

To select a power bus operating voltage, the electronic controller (550)polls each device port to gather power characteristics of all of theconnected power devices and makes a determination as to which devicesconnected to the device ports require a power conversion to connect tothe power bus based on the present power bus operating voltage. If noconversions are required, the power devices are connected to the powerbus without power conversion over non-converted power channels (5080,5085, 5090, and 5095). If power conversions are required and the presentpower bus operating voltage is suitable for the present power managerconfiguration, the electronic controller (550) configures theappropriate power converter(s) to make the required power conversion andthen connects the power external power devices that need a powerconversion to the to the power bus over a power converter (510, 515,520, 525).

In a further evaluation step the electronic controller processes one ormore bus voltage evaluations to determine if there is a more suitablebus voltage for the present power manager configuration and if so, theelectronic controller (550) resets the power bus operating voltage to anew operating voltage selected from the list of voltage operating pointsand reconfigures power converters and reconnects the external powerdevices to the power bus over the same or different connection paths.The electronic controller (550) periodically polls each device port torefresh system information including the power characteristics ofexternal power devices connected to device ports and repeats the powerbus operating voltage evaluation described above as the configuration ofthe power manager changes due to added or removed power deviceconnections and/or changes in power characteristics of connecteddevices.

6 EXAMPLES 6.1 Example 1 Operating Mode

The electronic controller (550) has previously set the power busoperating voltage to a desired power bus voltage or to a default busvoltage such as at initial power up. The electronic controller stores aplurality of power bus operating voltage values that it can operate withand also stores power manager performance criteria in a memoryassociated with the power manager. The electronic controller polls eachdevice port and determines the power characteristics of all of theconnected power devices (530, 540) and compares the powercharacteristics (e.g. operating voltage range) of all of the connectedpower devices with the present power bus operating voltage value. Theelectronic controller then uses one or more rules or algorithms storedin the memory module to determine if the present power bus operatingvoltage value should be maintained or changed to meet one or more of thedesired operating criteria. If the present power bus operating voltagevalue is acceptable and the device configuration has not changed fromthe last time the electronic controller polled the device ports, nochanges in operating parameters of the power manager are carried out. Ifthe present power bus operating voltage value is acceptable and thedevice configuration has changed from the last time the electroniccontroller polled the device ports, the electronic controller makes theappropriate operating parameter adjustments such as to connect a powerdevice to the bus with or without a conversion by actuating appropriateswitches (not shown) and setting power converter operating points asrequired to connect power devices to the power bus. However, if theelectronic controller determines that a change to the power busoperating voltage will better meet one or more power manager operatingcriteria defined in the energy management schema, it resets the powerbus operating voltage value to one of the voltage values stored inmemory and, if needed, makes the appropriate changes to power managerdevice settings and connections. Such changes include readjusting powerconverter settings to accommodate the new power bus voltage value,connecting power devices that require power conversion to the busthrough one or more power converters, and connecting power devices withpower requirements that match the new power bus voltage directly to thepower bus without a power conversion.

6.2 Example 2 Algorithm for Minimizing Power Conversion Losses

In one particularly beneficial embodiment, the electronic controller(550) uses the below listed algorithm to minimize power loss due topower conversions when a single power source is connected to the powermanager. This algorithm uses the fundamental relationship that powerlost in a converter is proportional to the difference between the powerconverter input and output voltages multiplied by a loss factor. Theloss factor is generally power converter dependent and may vary from onepower converter type or model to another. Additionally loss factor maydepend on input to output current amplitude ratio which can bedetermined from the input and output voltage and the total power beingconverted. Accordingly for a given system, loss factor values maycomprise a preset value depending on power converter type plus a currentratio estimate based on voltage ratio and total power being converted.Otherwise loss factors for various conditions can be stored in a look uptable or estimated in various other ways. Alternately the algorithm canbe simplified to only consider the voltage difference across the powerconverters.

An illustrative, non-limiting example of use of the algorithm follows.In this example, the system includes one input and one output powerconverter. The algorithm can be expanded to use any number of input andoutput power converters.

-   1) Detect the operating voltage and current of the power source and    each of the power loads.-   2) Does the power source operating voltage range allow connection    with the power bus at the present power bus operating voltage?    -   a) Yes—Connect the power source to the power bus without        conversion, go to step 3.    -   b) No—Calculate a power bus voltage value that minimizes total        power loss through all converters in the system.-   i. Let Ls=input conversion loss per Volt difference converted for a    given input voltage and current in the input converter.-   ii. Let Lo=output conversion loss per Volt difference converted for    a given output voltage and current on the output converter.-   iii. Let Iin=The Input current to an input power converter.-   iv. Let Tout=the output current from an output power converter.-   v. Let Vin=the voltage at an input power converter.-   vi. Let Vout=the voltage at an output power converter.-   vii. Select Ls and Lo from a stored table of values based on Vin,    Vout, Iin, and Tout requirements.-   viii. Select Vbus by minimizing:    Ls*|Vin −Vbus|+Lo*|Vout−Vbus|  Equation 2-   ix. Select a Vbus value stored in memory that most closely matches    the Vbus value calculated in Equation 2.-   x. Set the input power converter to connect the input source to the    power bus with the power bus voltage value equal to the selected    Vbus value, go to step 3.-   3) Set output power converter(s) to power any output device(s) from    the power bus at the present power bus voltage value.

Further illustrative, non-limiting, examples include the of use of thealgorithm for minimizing power conversion losses expanded to one or moreinput power conversions and/or one or more output power conversion. Whena single input power conversion and multiple output power conversionsare required, selecting Vbus includes minimizing the equation:

$\begin{matrix}{\left( {{Ls}*{{{Vin} - {Vbus}}}} \right) + {\sum\limits_{y = 1}^{n}\left( {{Lo}_{y}*{{{Vout}_{y} - {Vbus}_{y}}}} \right)}} & {{Equation}\mspace{14mu} 3}\end{matrix}$

-   -   Where: n=number of output power conversions; and where Lo may        not be the same for each output power converter        Where multiple input power conversions and multiple output power        conversions are required, selecting Vbus includes minimizing the        equation:

$\begin{matrix}{{\sum\limits_{x = 1}^{m}\left( {{Ls}_{x}*{{{Vin}_{x} - {Vbus}_{x}}}} \right)} + {\sum\limits_{y = 1}^{n}\left( {{Lo}_{y}*{{{Vout}_{y} - {Vbus}_{y}}}} \right)}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

-   -   Where: m=number of input power conversions; and n=number of        output power conversions; where Ls may not be the same for each        input power converter; and where Lo may not be the same for each        output power converter.

6.3 Example 3 Practical Example for Minimizing Conversion Power Loss

As can be seen from examining Equations 1 and 2, the power loss isminimized by minimizing the difference between the input and outputpower conversion. As an example, referring to FIG. 5, the power manager(500) has a default bus voltage value of 15 volts. A 30 volt powersource (530 a) is connected to one of the input ports (503 a) and 30volt power loads (540 a and 540 b) are connected to each of the twooutput ports (504 a and 504 b). The output loss, Lo, is the same foreach output power conversion. The algorithm described above determinesthat the input loss is 15Ls based on the difference Vin-Vbus and thatthe output loss Lo is 30Lo based on 2×Vout−Vbus (i.e. one loss for eachoutput device). Thus, the simple answer is to make Vbus equal to 30volts, which allows all three devices to be connected to the power buswithout a power conversion. However, the algorithm then checks thelookup table for 30 volts but finds that 28 volts is the closest matchand the bus voltage is set to 28 Volts. In the next step, the inputpower converter (515) is set to convert the 30 volt input source (530 a)to 28 volts for connection to the power bus (505). In step 3, each ofthe output converters (520) and (525) are set to convert the 28 voltpower bus voltage to 30 volts to power the 30 volt power loads (540 aand 540 b). In this case where the bus voltage is set to 28 volts thepower loss is 2Ls on the input side and 4Lo on the output side. This thepower loss is decreased from 15 Ls+30Lo to 2Ls+4Lo.

It will also be recognized by those skilled in the art that, while theinvention has been described above in terms of preferred embodiments, itis not limited thereto. Whereas exemplary embodiments include specificcharacteristics such as, for example, numbers of device ports, certainbus voltages and voltage ranges, power converter ranges, DC-to-DC powerconversion, those skilled in the art will recognize that its usefulnessis not limited thereto. Various features and aspects of the abovedescribed invention may be used individually or jointly. Further,although the invention has been described in the context of itsimplementation in a particular environment, and for particularapplications (e.g. implemented within a power manager), those skilled inthe art will recognize that its usefulness is not limited thereto andthat the present invention can be beneficially utilized in any number ofenvironments and implementations where it is desirable to selectivelyconnect power devices to a common power bus and to manage powerdistributing and minimize power losses due to power conversions or otherfactors related to power parameters of power devices. Accordingly, theclaims set forth below should be construed in view of the full breadthand spirit of the invention as disclosed herein.

What is claimed is:
 1. A power manager comprising: a power bus operatingat a first DC bus voltage; an electronic controller including a memorymodule; a plurality device ports each configured to interface with anexternal DC power device; a power converter channel disposed betweeneach device port and the power bus wherein each power converter channelincludes a unidirectional DC to DC power converter and one or moreswitches each operable by the electronic controller to connect thedevice port to or disconnect the device port from the power bus withappropriate power conversion settings; a direct power channel disposedbetween each device port and the power bus wherein each direct powerchannel includes one or more switches operable by the electroniccontroller to directly connect the device port to or disconnect thedevice port from the power bus; wherein at least one power convertingchannel includes a unidirectional DC to DC input power converter havingan input side and an output side disposed along the power convertingchannel between the power bus and an input device port wherein the inputpower converter input side connects to the input device port and theinput power converter output side connects to the power bus; wherein atleast one power converting includes a unidirectional DC to DC outputpower converter having an input side and an output side disposed alongthe power converting channel between the power bus and an output deviceport wherein the output power converter output side connects to theoutput device port and the output power converter input side connects tothe power bus; a bus sensor module in communication with the electroniccontroller configured to sense the first DC bus voltage; and, energymanagement schema operating on the electronic controller operable to;determine for each external DC power device interfaced with one of theplurality of device ports a device type and an operating voltage rangethereof; generate a list of external DC power devices to connect to theDC power bus as a power source; generate a list of external DC powerdevices to connect to the DC power bus as a power load; determine apower conversion setting, based on the first DC bus voltage, for eachexternal DC power device that has a non-bus compatible operatingvoltage; and, calculate a total power conversion loss associated withthe power conversion settings.
 2. The power manager of claim 1 whereinthe energy management schema calculates at least one second total powerconversion loss associated with at least one second power conversionsettings wherein the second power conversion settings are based at leastone second DC bus voltage.
 3. The power manager of claim 2 wherein theenergy management schema resets the DC bus voltage to one of the of atleast one second DC bus voltage to reduce the total power conversionloss.
 4. The power manager of claim 3 wherein the one or more switchesincludes: a first switch disposed along the input power convertingchannel between the input side of the input power converter and theinput device port; and a second switch disposed along the output powerconverting channel between the output side of the output power converterand the output device port, and, a third switch disposed along eachdirect power channel between the device port and the power buse.
 5. Thepower manager of claim 4 further comprising: a communication module incommunication with the electronic controller; a plurality communicationchannels with at least one communication channel extending from thecommunication interface to each of the plurality of device ports;wherein the communication interface, the plurality of communicationchannels and the plurality of device ports are operable to receive datafrom each external DC power device connected to the power manager and tocommunicate the received data to the electronic controller, wherein thereceived data at least includes a device type and an operating voltageof the external DC power device.
 6. The power manager of claim 4 whereinthe input side of the input power converter is connected to a secondinput device port, further comprising another first second switch,operable by the electronic controller, disposed along the input powerconverting channel between the input side of the input power converterand the second input device port.
 7. The power manager of claim 6wherein the output side of the output power converter is connected to asecond output device port, further comprising another second switch,operable by the electronic controller, disposed along the output powerconverting channel between the output side of the output power converterand the second output device port.
 8. The power manager of claim 1further comprising: a universal power channel extending between theoutput side of the output power converter and the input device port; anda fourth switch, operable by the electronic controller, disposed alongthe universal power channel between the output side of the output powerconverter and the input device port.
 9. A method for operating a powermanager that comprises, a plurality of device ports, an electroniccontroller in communication with each device port, a data storage modulein communication with the electronic controller, a power bus that can beoperated at a plurality of different discreet DC bus operating voltages,a power converting channel that includes a unidirectional DC to DC powerconverter and a first switch disposed between each device port and thepower bus, a direct connect channel and a second switch disposed betweeneach device port and the power bus, and at least two external DC powerdevices electrically interfaced with two different ones of the pluralityof device ports comprising the steps of: receiving, by the electroniccontroller, data from each of the at least two external DC powerdevices, wherein the data at least includes a device type and anoperating voltage range of the external DC power device; comparing, bythe electronic controller, the operating voltage range of each externalDC power device with a present DC bus operating voltage; calculating, bythe electronic controller, for the present DC bus operating voltage, afirst total power conversion loss associated with connecting eachexternal DC power device that has a non-bus compatible voltage to thepower bus over the power converter channel; selecting, by the electroniccontroller, one or more second DC bus operating voltages; calculating,by the electronic controller, one or more second total power conversionlosses associated with connecting each external DC device that has anon-bus compatible voltage to the power bus; and selecting, by theelectronic controller, a DC bus operating voltage associated with thelowest total power conversion loss.
 10. The method of claim 9 furthercomprising setting, by the electronic controller, the DC bus operatingvoltage to match the DC bus operating voltage associated with the lowesttotal power conversion loss the second DC bus operating voltage that isassociated with the smallest total power conversion loss.
 11. The methodof claim 9 further comprising: selecting, by the electronic controller,based on the present DC bus voltage, one or more external DC powerdevices that have a bus compatible voltage for direct connection to thepower bus over a direct power channel; configuring, by the electroniccontroller, based on the present DC bus voltage, power converteroperating points for connecting each external DC power devices having anon-bus compatible operating voltage to the power bus; and, operating,by the electronic controller, one or more switches as required toconnect the selected one or more external DC power devices to the powerbus over appropriate power channels.
 12. A power manager comprising: anelectronic controller and associated memory module; two input deviceports each connectable to the power bus over an input power converterchannel disposed between the power bus and each of the two input deviceports; two output device ports each connectable to the power bus over anoutput power converter channel disposed between the power bus and eachof the two output device ports; a unidirectional DC to DC input powerconverter disposed between the power bus and each of the two inputdevice ports wherein the unidirectional DC to DC power converterincludes an input side connected with each of the two input device portsand an output side connected with the power bus; a unidirectional DC toDC output power converter disposed between the power bus and each of thetwo output device ports wherein the unidirectional DC to DC includes aninput side connected with the power bus and an output side connected toeach of the two output device ports; a direct power channel associatedwith each of the two input device ports and the two output device portswherein each direct power channel directly connects a correspondingdevice port to the power bus; a first switch controllable by theelectronic controller, disposed along the direct power channel betweenthe corresponding device port and the power bus; a second switchcontrollable the electronic controller disposed between each one of thetwo input device ports and the input power converter input side; a thirdswitch controllable by the electronic controller disposed between eachone of the two output ports and the output side of the output powerconverter; wherein the power bus is operable at a plurality of differentDC bus operating voltages; and, wherein the electronic controlleroperates to calculate a total power conversion loss associated with eachof the plurality of different DC bus operating voltages and to selectfrom the plurality of different DC bus voltages a present DC bus voltagethat is suitable for minimizing the total power conversion loss.
 13. Thepower manager of claim 12 further comprising: a first universal powerchannel extending between the output side of the output power converterand a first of the two input ports; a fourth switch controllable by theelectronic controller disposed along the first universal power channelbetween the output side of the output power converter and the first ofthe two input ports; wherein the power manager is operable to connect anexternal DC power device connected to the first of the two input portsto the power bus over any one of a direct power channel, the input powerconverter and the output power converter.
 14. The power manager of claim13 further comprising: a second universal power channel extendingbetween the output side of the output power converter and a second ofthe two input ports; a second fourth switch controllable by theelectronic controller disposed along the second universal power channelbetween the output side of the output power converter and the second ofthe two input ports, wherein the power manager is operable to connect anexternal DC power device connected to the second of the two input portsto the power bus over any one of a direct power channel, the input powerconverter and the output power converter.
 15. The power manager of claim14 wherein the one or more substantially constant DC bus voltageoperating points range between 4 and 34 volts.